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Noisy Router Investigation

Graham21
Grafter
Posts: 72
Registered: 23-08-2012

Noisy Router Investigation

Hi, I thought I would start a new thread to let you know where we are at with noisy routers.
We are currently investigating 4 or 5 cases.
We have had three routers sent in to us which were meant to be noisy. We tried them here and couldn't find any difference between them and the various routers that we have in the office. If you hold the router to your head, you might here a bit of electrical noise. That's all we found.
I took one of the routers home last night to try (from Aspjashley1) and found no difference between it and the router that I have been using at home since December..
We have one customer who has been sent several replacements and they all make a noise. Interestingly, they only make noise in their village. Four miles down the road they are silent!
I will be crossing the Pennines later today to investigate and I will take various routers with me.
We used to ship ADSL routers with USB ports. I'm taking a USB router with me with ADSL firmware on it as one of the theories from this forum is that this particular hardware version does not suffer from this problem.
Graham

136 REPLIES
Community Veteran
Posts: 19,101
Thanks: 443
Fixes: 21
Registered: 31-08-2007

Re: Noisy Router Investigation

Just so that you are aware, http://community.plus.net/forum/index.php/topic,113121.0.html was an earlier thread on this topic
PS. There have been suggestions on it depending on how good your hearing is Wink
apjashley1
Grafter
Posts: 307
Registered: 31-07-2012

Re: Noisy Router Investigation

The noise only happens when there's an active ADSL connection - just plugging them in won't reproduce it. As my master socket is in the bedroom it was really really annoying! Thankfully the replacement (with USB) doesn't do it.
Graham21
Grafter
Posts: 72
Registered: 23-08-2012

Re: Noisy Router Investigation

Hi Aspjashley1
I took your router with me across the Pennines to the house of another customer who has reported noise.
She took me into the room with the router in it and said "Can you hear that?" I couldn't hear anything. Not unless I put my ear to it. Then I could hear a bit of crackling / static. Very subtle though.
I swapped her router for a fibre one reflashed to ADSL firmware and she said that she couldn't hear the noise anymore.
To my ears and hers, yours made the same sound and it seems that you have found the same solution.
I have sent yours and her router to Technicolor. Let's see what they say.
Graham

Razer
Grafter
Posts: 1,398
Thanks: 6
Registered: 17-11-2012

Re: Noisy Router Investigation

Have you managed to get those pre-paid bags made yet? As soon as they're done and you send me them I can return my routers to you.
Interesting that you couldn't hear it, though I'm not really surprised.
Community Veteran
Posts: 2,286
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Registered: 18-02-2013

Re: Noisy Router Investigation

1 of our kids has a computer with coil whine, and he has to turn his pc off at the plug socket at night, incidentally, none of us can hear it. That is the psu at idle making a noise. Quite common apparently!
Community Veteran
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Registered: 08-01-2008

Re: Noisy Router Investigation

Quote from: Graham21
We tried them here and couldn't find any difference between them and the various routers that we have in the office.

Has anyone thought of checking these with a sound meter (specifically one that can test different frequency ranges)?
Call me 'w23'
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Opinions expressed in forum posts are those of the poster, others may have different views.
Community Veteran
Posts: 3,188
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Registered: 31-07-2007

Re: Noisy Router Investigation

More likely we are used to the noise.  So a hypothetical question your fridge/freezer, can you tell if its on or off  Same difference for anything that is powered 24/7, you become used to its noises so the suggestion of a sound meter rules out that fact
Unvalued customer since 2001 funding cheap internet for others / DSL/Fibre house move 24 month regrade from 8th May 2017
jimbof
Grafter
Posts: 348
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Registered: 02-05-2013

Re: Noisy Router Investigation

Could quite easily be capacitor whine.
I recently had to reject a motherboard for a project at work because a single surface mount capacitor in the fan control circuit would make an unbearable whine.  The manufacturer sent a replacement sample which they thought was fine, same problem.  I could fix it by replacing the capacitor with something better.  Could I get them interested to fix the problem, even telling them what part to replace?  Of course not.  The part they needed to fit was 10x more expensive.
Community Veteran
Posts: 2,286
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Registered: 18-02-2013

Re: Noisy Router Investigation

I think when you have a company supplying a product to you in a quantity of thousands, they may just sit up and listen.
Well it would be foolish not to at the end of the day,  from my point of view i wouldn't recommend one to a freind either.
Community Veteran
Posts: 19,101
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Registered: 31-08-2007

Re: Noisy Router Investigation

Just to point out that Inductors and Transformers can also resonate and emit noises.
Community Veteran
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Registered: 18-01-2013

Re: Noisy Router Investigation

As above (I'm an electronics engineer)
Some devices will make rustling noises with little or no load. Switching power supplies may chirp under low load conditions.
The most common causes for noise are badly wound inductors - these tend to have a high pitched whine which changes with load.
Capacitors (as mentioned above) also can act as mini speakers under certain frequencies.
It could just be the modem circuits making the noise (inductors/capacitors) but power supply noise would be more likely.
As a suggestion, can you test the faulty routers with some kind of load plugged into the USB port - i.e. a mobile phone charger ? This will put around half an amp of load onto the PSU and may induce the noise you've been experiencing. You may also find the orientation of the device changes the amplitude of the noise.
You could also open up the faulty units and connect a load to the regulator circuits and see if that makes much of a difference.
andy265
Grafter
Posts: 78
Registered: 30-08-2012

Re: Noisy Router Investigation

I have one of the ADSL 582n's with no USB that has made a high pitched whistle ever since I got it.
I'm the only one in the family that seems to be able to hear it though, and it was in the kitchen where there's normally noise from other things as well, so it doesn't bother me. I'm not using it now so if you want another one to look at you can have it back Smiley
rja66
Rising Star
Posts: 401
Thanks: 1
Fixes: 1
Registered: 31-07-2007

Re: Noisy Router Investigation

I also have an ADSL version that gently wines, although this is only really noticeable when the room is quiet (TV off etc.). I have always heard it and yet my wife and daughter say they have never noticed it so this may well be a personal thing depending on an individuals hearing.
Funny, I've noticed it more since reading these threads !!  Smiley
That said, I wouldn't want it replaced as it performs really well in all other aspects, including a great wireless range which I note others have issues with.
andy265
Grafter
Posts: 78
Registered: 30-08-2012

Re: Noisy Router Investigation

The wireless on mine didn't seem very good when I tested it, but I have a separate access point anyway so normally the wireless on the router is turned off.